Vehicle seats tend to become uncomfortable when the driver or passenger remains in a seated position for a long period of time. The primary area of discomfort is in the lumbar or lower back region.
Typically, while there are provisions for horizontal and tilting adjustments of vehicle seats, the selected contour of the typical seat for the average size occupant does not conform to all body shapes. Hence, it is desirable to provide means for adjusting the contour of the back support of the seat.
Various arrangements have been used satisfactorily in the past to control the pressure in back and/or seat portions of a vehicle seat. For example, see the Switch and Valve Assembly in Manning et al U.S. Pat. No. 4,633,763, wherein a push button and associated stem serve to partially open a normally closed valve to bleed off fluid under pressure from a lumbar area bladder when the push button is partially depressed, and to close a switch and actuate a pump to inflate the bladder when the push button is fully depressed.
Von Heck U.S. Pat. No. 4,114,214 includes a seat filled with expanded polystyrene micro-bearings and a switch actuated pump system which reverses to either pump up or pump down a seat cushion. A second switch is operated in conjunction with the pump reversing switch to control a solenoid valve.
Imaoka et al U.S. Pat. No. 4,722,550 discloses a pump up system which changes the hardness of the seat or back portions in response to outputs from detecting means for detecting running conditions of the motor vehicle.
Von Heck U.S. Pat. No. 3,608,961 illustrates and describes a seat cushion filled with a plurality of plastic beadlike material deformable from a generally spherical shape into a multifacet structure as a result of seat pressure control with a vacuum pump and a simple valve.
Vanderbilt et al U.S. Pat. No. 3,326,601 describes an inflatable seat back which is pumped up by a non reversible air pump and then vented to the atmosphere by virtue of the operator pushing against the seat.
Horvath et al U.S. Pat. No. 4,707,027 discloses a vehicle seat having a pneumatic lumbar selectively connected with a reversible pump via a solenoid valve. When it is desired to power down the air from the lumbar bladder, a switch is actuated to open the solenoid valve and simultaneously start the reversible motor in an opposite direction via a relay and a contact.